1. Field of the Disclosure
The disclosure refers to a surgical manipulation instrument comprising a coupling detachably connecting an extra-corporeal drive portion and a partially intra-corporeal manipulator part.
2. Discussion of the Background Art
Surgical instruments that are not designed for single use, but for multiple use, have to be sterilized after each single use. Sterilizing can be performed using non-thermal or thermal methods. In everyday clinical practice, sterilizing is generally performed using thermal methods, in particular the so-called autoclaving. In autoclaving, the instrument to be sterilized is exposed for a certain time to water vapor under very high pressure which must wet all surfaces to be sterilized. In the autoclave, the instrument to be sterilized is exposed to temperatures up to 156° C. and pressures up to 2 bar for a period of up to 40 min. Autoclaving must be repeated after each use of the instrument so that in the course of an instrument's lifetime up to several hundreds of autoclaving processes may be passed.
Ever since the 1980ies, the importance of so-called minimally invasive surgery has increased. Here, long, slender manipulation instruments are advanced through only small openings in the epidermis. The intra-corporeal operative field is observed using a rod-shaped camera, introduced in the same manner, and an extra-corporeal monitor. Minimally invasive surgery offers advantages in particular for the patient, namely little traumatizing, short convalescence times, less post-operative pain, lower blood loss, lower risk of infection, lower risk of wound healing disturbances, better cosmetic results, etc. The disadvantages of minimally invasive surgery include, among others, the limited freedom of movement of the surgical instruments. Since the passage opening in the epidermis and the fat tissue can be seen as being a stationary opening forming an invariable point, this results in inverted movement ratios or an impeded hand-eye coordination with respect to the monitor image. Two degrees of freedom of movement are bound by the invariable point, i.e. not every point in the working area can be reached under any optional orientation of the functional instrument end.
Minimally invasive manipulation instruments that offer additional intra-corporeal degrees of freedom of movement may provide enhanced intra-corporeal manipulability and thus represent a considerable improvement in minimally invasive surgery. The additional degrees of freedom have to be moved precisely. This may possibly be achieved by manual operation, however, this requires great aptness and long practice. Therefore, a robot-assisted remote manipulation approach is advisable, where the surgeon sits at an ergonomically shaped console, remote from the patient, and guides the surgical manipulation instrument via an appropriate man-machine interface without having to think about the cinematic and its activation. Here, the surgical manipulation instrument is actuated in a computer-assisted manner and performs the movement corresponding to the surgeon's intentions.
However, the actuators for driving the surgical manipulation instrument can generally not be autoclaved. Therefore, it is required that the extra-corporeal drive portion is separable from the partially intra-corporeal manipulator part.
The surgical manipulation instrument is thus bipartite and, by means of a coupling, is adapted to be separated into an extra-corporeal drive portion and an intra-corporeal manipulator part.
A surgical manipulation instrument is known from U.S. Pat. No. 6,491,707 A1, which comprises a coupling for separating the drive portion from the manipulator part. Here, the drive device rotates actuation elements such as shafts and transmits the rotational and torsional movements to actuation elements of the manipulator part via the coupling device. The end effector of the manipulator part is actuated through the second actuation elements. The coupling parts each have rotatable coupling bodies comprising axial pins and bores, respectively, and are coupled or uncoupled in the axial direction. Since the rotatable opposite coupling bodies cannot be coupled together if they are not in precise alignment, a search run must be performed for all coupling body pairs upon coupling. The coupling bodies each rotate until a position is found in which all coupling body pairs are in a coupling position that allows engagement. A similar coupling is known from US 2001 003 1983 A1. Here, the coupling pats comprise semi-cylindrically shaped coupling bodies. In the interest of a smooth coupling operation it is necessary to provide a certain minimum play between the coupling bodies in the engaged condition. However, this play has adverse effects in the operation of the manipulation instrument or may even make an automatic control impossible.
It is an object of the disclosure to provide a surgical manipulation instrument comprising axially displaceable elements both on the drive side and on the manipulator side, wherein the actuation elements are connected by means of a reliable and simple coupling device.